Pyridyl propionitrile and pyridyl propionamide derivatives



United States Patent 3,254,092 PYRIDYL PROPIONITRILE AND PYRIDYL PROPIONAMIDE DERIVATIVES Joseph Albert Meschino, North Wales, Pa., assignor to McNeil Laboratories, Incorporated, a corporation of Pennsylvania N0 Drawing. Filed July 17, 1964, Ser. No. 383,488 3 Claims. (Cl. 260-294.9)

This is a continuation-in-part'of application Serial No. 103,985, filed April 19, 1961 now U.S. Patent No. 3,185,707.

This invention relates to a new series of organic compounds represented by the following general formula CHzOR and methods for their preparation.

Z in the above general formula stands for nitrile or carboxamide, and A represents aryl, substituted aryl or hydrogen. Aryl includes monocyclic aryl, such as phenyl and fused rings, such as naphthyl which may be substituted by lower alkyl, lower alkoxy, amino, halo or am'inoalkyl groups.

In the above general formula, X stands for pyridyllower alkyl.

R in the above general formula represents hydrogen; amino carbonyl wherein the amine group is primary, secondary or tertiary; or an acyl function. Examples of such substituents include lower alkylaminocarbouyl, dilower alkylaminocarbonyl, i.e. dimethylaminocarbonyl, diethylaminocarbonyl, N-cyclopentyl-N-methylaminocarbonyl, N-benzyl-N-methylaminocarbonyl, pyrrolidinocarbonyl, piperidinocarbonyl, 4-methyl-piperidinocarbonyl,

morpholinocarbonyl, thiamorpholinocarbonyl, piperazioncarbonyl, or 4-methylpiperazinocarbonyl. Examples of acyl groups include radicals of aromatic, aliphatic, heterocyclic or araliphatic carboxylic acids, such as a lower fatty acid, e.g., acetic or :propionic; a phenyl carboxylic acid, e.g., alkoxyphenyl carboxylic acid, such as 4-methoxy benzoic acid; 3,4-dimethoxybenzoic acid; 3,4,5-trimethoxybenzoic acid; 3,4-methylenedioxy benzoic acid; syringic acid; O-carbalkoxysyringic acid; alkoxyphenyl aliphatic carboxylic acid, e.g., alkoxycinnamic acid.

A variety of methods may be employed for the preparation of the novel compounds of this invention. However, a particularly useful and unique method has been found which is superior and is distinguishable from those presently known. It is intended that this method be included in the scope of the present invention. In a general way, the novel process comprises reducing the appropriate nitrile ester 'With a hydrogenating agent in the presence of an organic solvent, if so desired, to obtain the corresponding alcohol. Preferred reducing agents for this purpose are the metal hydn'des, such as lithium aluminum alkoxy hydrides, e.g. lithium aluminum tritertiary butoxy hydride, lithum aluminum triethoxy hydride, or lithium aluminum triisopropoxy hydride; alkali metal borohydrides, e.g. potassium borohydride, sodium borohydride, or lithium borohydride; diboranes and substituted boranes, such as alkyl substituted boranes. Suitable as solvents for the reduction reaction are the inert organic or water miscible organic solvents, such as the lower alkanols, e.g., methanol, ethanol, or preferably 2-propanol. Alternatively, tetrahydrofuran, ether dioxane, benzene, toluene, xylene or di-n-butyl ether may be employed.

Those compounds in the novel series wherein Z represents carboxamido may be obtained by hydrolysis of the corresponding nonester-bearing nitrile alcohols with an appropriate hydrolytic agent, such as sulfuric acid, p hosphoric acid, hydrochloric acid, alkali metal hydroxides,

ice

such as sodium hydroxide and potassium hydroxide or, preferably, hydrogen peroxide in the presence of a mild base such as an alkali metal hydroxide carbonate or bicarbonate. Further, the carbamoyl nitrile and carbomoyl amide derivatives are obtained by treating the alkanolic nitrile, or its functional derivative, i.e. carboxamide, with a reactive ester of a lower alkanol, e.g., a lower alkylcarba-mate, such as ethylcarbamate, in the presence of an aluminum alkoxide, e.g., aluminum isopropoxide and an organic solvent, such as toluene, benzene, xylene, hexane, heptane, tetrahydrofuran, carbon tetrachloride, chloroform, chlorobenzene, diethylether or dioxane.

Alternatively the carbamate series of the novel compounds of this invention may be prepared by reacting the appropriately substituted hydroxymethyl compound, i.e. one wherein, in the above general formula, R stands for hydrogen, successively with phosgene and ammonia.

Still another novel method which is intended to be included within the scope of the present invention relates to the preparation of those compounds of the present series wherein R is hydrogen and Z is nitrile by treating the apropriately di-substituted acetonitrile with formaldehyde in the presence of a weak base such as calcium oxide, alkali metal carboxate or bicarbonate or triethylamine.

The novel compounds of this invention are useful as central nervous system depressants. They may be used in admixture with suitable nontoxic solid or liquid carriers in the form of tablets, pills, capsules, or in liquid form, such as solutions, suspensions or emulsions. They may be admixed, if desired, with other compatible and physiological substances.

The following examples are intended to illustrate, but not to limit, the scope of the invention.

Example I A cold solution of 10.7 parts by weight of 4-pyridinecarboxaldehyde, 1l .2 parts by weight of ethyl cyanoacetate and 0.4 part by volume of piperidine in 30 parts by volume of dioxane is allowed to stand for about eight hours. The mixture is brought to room temperature and diluted with water. The crystalline precipitate is filtered and dried to yield ethyl alpha-cyano-beta-(4-pyridyl) acrylate, melting point 103 C.104 C.

To a cooled stirred suspension of 5.2 parts by weight of sodium borohydride in 45 parts by volume of 2-propanol is added slowly 10.1 parts by weight of solid ethyl alpha-cyano-beta-(4-pyridyl)a-crylate. The mixture is stirred at room temperature for about eight hours, after which the excess borohydride is destroyed with dilute hydrochloric acid. The resulting :mixture is concentrated under reduced pressure to remove most of the Z-prO-panol. The residue is made basic with potassium bicarbonate and shaken with methylene chloride. The organic layer is then dried over anhydrous potassium carbonate and concentrated to dryness. The residue is crystallized to yield alpha-hydroxymethyl-beta-t 4-pyridyl propionitrile, melting point 65 C.68 C. Recrystallization from chloroform-ether raises the melting point to 68 C.69 C.

Example 11 A cold solution of 21.4 parts by weight of Z-pyridinecarboxaldehyde, 22.6 parts by weight of ethyl cyanoacetate and 0.8 part by volume of piperidine in 60 parts by volume of dioxane is allowed to stand for one hour, after which it is brought to room temperature and diluted with water. The crystalline precipitate is filtered and dried to give ethyl alpha-cyano-beta-(2-pyridyl)acrylate, melting point C.94 C.

To a cooled, stirred suspension of 5.2 parts by weight of sodium borohydride in 45 parts by volume of 2- .beta-(3-pyridyl)propionitrile.

propanol is added slowly 10.1 parts by weight of ethyl alpha-cyano-beta-(2-pyridyl)acrylate. The mixture is stirred at room temperature for a period of eight hours, after which the excess borohydride is destroyed with dilute hydrochloric acid. The resulting mixture is concentrated under reduced pressure to remove most of the Z-propanol. The residue is made basic with potassium carbonate and shaken with methylene chloride. The organic layer is dried over anhydrous potassium carbonate and concentrated to dryness, leaving the alpha-hydroxymethyl-beta- (2-pyridyl)propionitrile as a liquid.

Example III A mixture of 7.3 parts by weight of alpha-hydroxymethyl-beta-(4-pyridyl)propionitrile, 4.6 parts by weight of ethyl carbamate and 1 part by weight of aluminum isopropoxide in 100 parts by volume of toluene is brought to refluxunder an asbestos jacketed Vigreux column and distillation effected until the head temperature reaches 110 C. Refluxing is continued for one hour, after which most of the toluene is removed under reduced pressure. The reaction product is alpha-carbamoyloxymethyl-beta-(4-pyridyl)propionitrile.

Example IV In Example I, an equivalent amount of S-pyridine-carboxaldehyde is substituted for the 4-pyridyl-carboxaldehyde. The reaction product is alpha-hydroxymethyl- Example V A mixture of 7.3 parts by weight of alpha-hydroxymethyl-beta-(4-pyridyl)propionitrile and 125 parts by volume of 20 percent hydrogen peroxide is made homogeneous with acetone. To this is added 30 parts by volume of a percent solution of sodium carbonate and the mixture is stirred for three days at room temperature.

After destroying the excess peroxide with platinum, the mixture is concentrated under reduced pressure to give alpha-hydroxymethy1-beta-(4-pyridy1) propionamide.

Example VI Example VII A mixture of 16.2 parts by Weight of alpha-hydroxymethyl-beta-(4-pyridy1)propionitrile and 11.9 parts by weight of phenylisocyanate is heated on a steam bath for a period of thirty minutes, after which it is triturated and washed with ligroin. The reaction product is alpha-(N- phenylcarbamoyloxy methyl) beta (4 pyridyl) propionitrile.

What is claimed is:

1. A compound of the formula wherein Z is a member of the group consisting of nitrile and carbamoyl; X is pyridyl-loweralkyl; and R is a member of the group consisting of hydrogen, carbamoyl and N-phenyl carbamoyl.

2. The compound alpha-hydroxymethyl-beta-(4-pyridyl)pr-opionitrile.

3. The compound alpha-hydroxymethyl-beta-(2-pyridyl)propionitrile.

No references cited.

WALTER A. MODANCE, Primary Examiner. 

1. A COMPOUND OF THE FORMULA
 2. THE COMPOUND ALPHA-HYDROXYMETHYL-BETA-(4-PYRIDYL)PROPIONITRILE. 